Device and method for testing water resistance of pile side grouting fluid while drilling

Abstract

The present invention relates to the technical field of pile foundation engineering test, and specifically discloses a device for testing the water resistance of grouting liquid on the side of a pipe pile while drilling, comprising a model box system, a water supply system, and a grouting system; the model box system comprises a model box, a bottom model pile, and a soil body, wherein a simulated borehole is arranged in the soil body; the water supply system comprises a horizontal water supply subsystem and a vertical water supply subsystem, and the model box is provided with a horizontal water inlet, a horizontal water outlet, a vertical water inlet, and a vertical water outlet, the water outlet of the horizontal water supply subsystem is connected to the horizontal water inlet, and the water outlet of the vertical water supply subsystem is connected to the vertical water inlet. Grouting holes are arranged on the model pile; the grouting outlet of the grouting system is connected to the grouting holes. The device for testing the water resistance of grouting liquid on the side of a pipe pile while drilling of the present invention has a simple structure, uncomplicated processing technology, low processing cost, light weight, convenient transportation, simple operation process, easy to learn and use, and good safety.

Description

Technical Field

[0001] The invention relates to the technical field of pile foundation engineering tests, and in particular to a device and method for testing the water resistance of a pile side grouting liquid for a pipe pile while drilling. Background Art

[0002] The pipe pile while drilling is an environmentally friendly large-diameter (800-1400mm) non-soil-squeezing pipe pile that can drill holes, sink piles and discharge soil simultaneously without mud discharge. The successful development of this type of pile has solved the problem of pile sinking caused by large pile diameter or hard soil layer. The super strong stratum adaptability enables large-diameter pipe piles to penetrate medium and slightly weathered rock layers, and achieves full rock embedment at the pile end, with high bearing capacity (compared with the ultimate bearing capacity of a single pile of the same diameter, it is 20.97%-64.24% higher); it avoids damage to the pipe pile body by hammering and static pressure methods; no mud wall protection is required during the construction process, which is more environmentally friendly and less noisy; the diameter of the pipe pile is expanded to 800-1400mm.

[0003] The unique construction process of this pile type creates a gap of about 10mm between the large-diameter pipe pile and the soil around the pile. Cement slurry or cement mortar needs to be poured into the gap to increase the friction resistance of the pile side and ultimately improve the bearing capacity of the pile foundation. In order to prevent leakage, before grouting, it is necessary to pour a certain thickness of cement slurry at the bottom of the inner cavity of the large-diameter pipe pile to seal the bottom. The rock embedding at the pile end and the grouting at the pile side fully illustrate that the drilling and pipe pile is an end-bearing friction pile. The effect of the pile side grouting determines the size of the pile side friction resistance of the drilling and pipe pile, which will ultimately greatly affect the ultimate bearing capacity of the drilling and pipe pile.

[0004] In the actual construction process of drilling and sinking piles while drilling and pipe piles, there is flowing groundwater in the stratum. In special cases, pressurized water may be encountered, causing water gushing and water inrush. The grouting environment in this case is obviously different from that in the absence of water or under static water. At present, most of the experimental studies on the side grouting effect of drilling and pipe piles are carried out under the absence of water or under static water. Therefore, the current experimental studies cannot obtain more accurate grouting effects and cannot provide more scientific guidance for the grouting site. Summary of the invention

[0005] In order to overcome the deficiencies of the prior art, the present invention provides a device for testing the water resistance of the pile side grouting fluid of the drilling pipe pile, which can simulate the flowing water of the formation, so that the experimental research can obtain a more accurate grouting effect.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A device for testing the water resistance of the pile side grouting liquid of the drilling pipe pile, comprising a model box system, a water supply system, and a grouting system;

[0008] The model box system comprises a model box and a model pile with a sealed bottom end; the model box is filled with soil, a simulated borehole is arranged in the soil, and the diameter of the simulated borehole is larger than the diameter of the model pile; the model pile is coaxially arranged in the simulated borehole; the side wall of the model box is provided with a plurality of transverse water inlets, the bottom plate of the model box is provided with a plurality of transverse water outlets and a plurality of vertical water inlets, and the top wall of the model box is provided with a plurality of vertical water outlets;

[0009] The water supply system comprises a horizontal water supply subsystem and a vertical water supply subsystem. The water outlet of the horizontal water supply subsystem is communicated with the horizontal water inlet, and the water outlet of the vertical water supply subsystem is communicated with the vertical water inlet.

[0010] The model pile is provided with a plurality of grouting holes for grouting into the gap between the model pile and the soil body; and the grouting outlet of the grouting system is communicated with the grouting holes.

[0011] Compared with the prior art, the present invention simulates stratum flowing water by setting a horizontal water supply subsystem and a vertical water supply subsystem, thereby obtaining the physical and mechanical properties M2 of the grouting liquid in the gap between the model pile and the soil under the action of flowing water and the grouting effect W2 after the grouting liquid in the gap solidifies; by closing the water supply subsystem, the physical and mechanical properties M1 of the grouting liquid in the gap and the grouting effect W1 after the grouting liquid in the gap solidifies in a waterless state can be obtained, and the anti-groundwater performance of the slurry can be judged by comparing the M1 with the M2 and the W1 with the W2. The device for testing the water resistance of the pile side grouting liquid of the drilling and pipe pile of the present invention has a simple structure, uncomplicated processing technology, low processing cost, light weight, convenient transportation, simple operation process, easy to learn and use, and good safety.

[0012] As an option, a first permeable stone layer is laid between the top plate of the model box and the soil, a second permeable stone layer is laid between the side wall and the soil, and a third permeable stone layer is evenly laid between the bottom end of the simulated borehole and the bottom plate; the lateral water outlet is arranged on the bottom plate corresponding to the setting position of the second permeable stone layer, and the vertical water inlet is arranged on the bottom plate corresponding to the setting position of the third permeable stone layer.

[0013] As an option, a plurality of water outlet pipes are vertically arranged on the top plate, and a plurality of vertical water outlets are arranged on the water outlet pipe at intervals along the vertical direction of the water outlet pipe.

[0014] Optionally, the vertical water supply subsystem includes a first water inlet pipe, a vertical water supply tank, and a first water filling machine; one end of the first water inlet pipe is connected to the vertical water inlet, and the other end is connected to the vertical water supply tank; the vertical water supply tank is connected to the air outlet of the first water filling machine.

[0015] As an option, the first water inlet pipe is provided with a first rotor flowmeter and a first valve.

[0016] As an option, the vertical water supply tank is provided with a first pressure gauge and a first exhaust valve.

[0017] Optionally, the water supply system includes a first water reservoir, and the vertical water supply subsystem also includes a first water pump and a first water pumping pipe; one end of the first water pumping pipe is arranged in the first water reservoir, and the other end is connected to the water suction port of the first water pump, and the water outlet of the first water pump is connected to the vertical water supply tank.

[0018] As an option, it also includes a water circulation system, which includes a clean water tank and a second water reservoir for receiving water flowing out of the model box, and the clean water tank is connected to the first water reservoir through a siphon.

[0019] Another aspect of the present invention provides a method for testing the water resistance of grouting fluid using the above-mentioned device for testing the water resistance of grouting fluid for pile side while drilling, comprising the following steps:

[0020] In a water-free state, grouting is performed into the gap, a portion of the grouting liquid in the gap is taken and the water-cement ratio, density, consistency, fluidity, compressive strength, elastic modulus and yield strength of the grouting liquid are obtained; after the grouting liquid in the gap solidifies to a predetermined strength, the three-dimensional geometric dimensions of the grouting liquid are obtained;

[0021] The water supply system is turned on, and grouting is injected into the gap in the presence of water. After the water discharge time of the model box reaches a preset time, part of the grouting liquid in the gap is taken and the water-cement ratio, density, consistency, fluidity, compressive strength, elastic modulus, and yield strength of the grouting liquid are obtained; after the grouting liquid solidifies to a predetermined strength, the water supply system is turned off and the three-dimensional geometric dimensions of the grouting liquid are obtained;

[0022] The water resistance of the grouting fluid is judged based on the changes in the water-cement ratio, density, consistency, fluidity, compressive strength, elastic modulus and yield strength of the grouting fluid in the anhydrous state and the water state, as well as the change characteristics of the three-dimensional spatial geometric dimensions of the solidified grouting fluid in the anhydrous state and the water state.

[0023] As an option, before opening the water supply system, the following steps are also included:

[0024] The horizontal water supply subsystem is closed, and the vertical water supply subsystem is opened until the water inflow of the vertical water inlet and the water outflow of the vertical water outlet are balanced;

[0025] The vertical water supply subsystem is closed, and the horizontal water supply subsystem is opened until the water inflow of the horizontal water inlet and the water outflow of the horizontal water outlet are balanced;

[0026] The vertical water supply subsystem and the horizontal water supply subsystem are opened until the water inflow of the vertical water inlet and the water inflow of the horizontal water inlet are balanced with the water outflow of the model box. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The present invention will be further described with reference to the accompanying drawings and specific embodiments:

[0028] Figure 1 It is a schematic diagram of the structure of the present invention;

[0029] Figure 2 It is a partial structural schematic diagram of the model box system of the present invention;

[0030] Figure 3 It is a partial structural schematic diagram of the model box system and the grouting system of the present invention;

[0031] Figure 4 It is a flow chart of testing the water resistance of the grouting liquid of the present invention.

[0032] In the figure:

[0033] 1. vertical water inlet, 2. first valve, 3. first water inlet pipe, 4. first rotor flowmeter, 5. siphon, 6. first water reservoir, 71. first pumping pipe, 72. second pumping pipe, 8. first pumping pump, 9. first air compressor, 10. vertical water supply tank, 11. first exhaust valve, 12. first pressure gauge, 13. second pumping pump, 14. second air compressor, 15. horizontal water supply tank, 16. second exhaust valve, 17. second pressure gauge, 18. second rotor flowmeter, 19. second valve, 20. model box, 201. top plate, 202. side plate, 203. bottom plate, 204. Horizontal water outlet; 205. Horizontal water inlet; 21. Second permeable stone layer; 22. Soil; 23. Grouting machine; 24. Pressure gauge; 25. Grouting switch; 26. Grouting pipe; 27. First permeable stone layer; 28. Model pile; 29. ​​First water outlet switch; 30. Third rotor flowmeter; 31. Second water outlet switch; 33. Fourth rotor flowmeter; 34. Second water reservoir; 35. Middle grouting hole; 36. Concrete sealing layer; 37. Gap; 38. Lower grouting hole; 39. Bolt; 40. Third permeable stone layer; 41. Cylindrical steel sleeve; 42. Clean water tank; 43. Screw hole. DETAILED DESCRIPTION

[0034] The preferred embodiments of the present invention are described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0035] Embodiment 1

[0036] like Figures 1 to 3 As shown, this embodiment discloses a device for testing the water resistance of the pile side grouting liquid of the drilling pipe pile, including a model box system, a water supply system, and a grouting system;

[0037] The model box system includes a model box 20 and a model pile 28 with a sealed bottom end; the model box 20 is filled with soil 22, and a simulated borehole is provided in the soil 22, and the diameter of the simulated borehole is larger than the diameter of the model pile 28; the model pile 28 is coaxially arranged in the simulated borehole, the side wall of the model box 20 is provided with a plurality of transverse water inlets 205, the bottom plate of the model box 20 is provided with a plurality of transverse water outlets 204 and a plurality of vertical water inlets 1, and the top wall of the model box 20 is provided with a plurality of vertical water outlets;

[0038] The water supply system includes a horizontal water supply subsystem and a vertical water supply subsystem, the water outlet of the horizontal water supply subsystem is connected to the horizontal water inlet 205, and the water outlet of the vertical water supply subsystem is connected to the vertical water inlet 1. That is, the horizontal water inlet 205 is arranged on the side plate 202, the horizontal water outlet 204 and the vertical water inlet 1 are arranged on the bottom plate 203, and the vertical water outlet is arranged on the top plate 201.

[0039] The model pile 28 is provided with a plurality of grouting holes for grouting into the gap 37 between the model pile 28 and the soil body 22; the grouting outlet of the grouting system is connected to the grouting holes.

[0040] Compared with the prior art, the present invention simulates stratum flowing water by setting a horizontal water supply subsystem and a vertical water supply subsystem, thereby obtaining the physical and mechanical properties M2 of the grouting liquid in the gap 37 between the model pile 28 and the soil 22 under the action of flowing water and the grouting effect W2 after the grouting liquid in the gap 37 solidifies; by closing the water supply subsystem, the physical and mechanical properties M1 of the grouting liquid in the gap 37 and the grouting effect W1 after the grouting liquid in the gap 37 solidifies in the waterless state can be obtained, and the anti-groundwater dispersion performance of the slurry can be judged by comparing M1 with the M2 and comparing W1 with W2. The device for testing the water resistance of the pile side grouting liquid of the drilling and pipe pile of the present invention is simple in structure, uncomplicated in processing technology, low in processing cost, light in weight, convenient in transportation, simple in operation process, easy to learn and use, and safe.

[0041] The soil 22 of this embodiment is not limited to silt, sand, clay, backfill soil, sandy soil, silty soil, etc., and may also be a mixture of various soils 22.

[0042] In this embodiment, a first permeable stone layer 27 is laid between the top plate 201 of the model box 20 and the soil 22, a second permeable stone layer 21 is laid between the side plate 202 and the soil 22, and a third permeable stone layer 40 is evenly laid between the bottom end of the simulated borehole and the bottom plate 203; the horizontal water outlet 204 is arranged on the bottom plate 203 corresponding to the setting position of the second permeable stone layer 21, and the vertical water inlet 1 is arranged on the bottom plate 203 corresponding to the setting position of the third permeable stone layer 40;

[0043] The particle size of the permeable stone is equivalent to that of pebbles, sand and gravel, which mainly plays the role of uniformly distributing water pressure. The particle size of the permeable stone should not be too small or too large, and 3-8 mm is appropriate. The permeable stone material is an inert material and cannot undergo physical or chemical reactions with the grouting liquid, thereby affecting the measurement results; the diameter of the third permeable stone layer 40 should be slightly larger than the diameter of the simulated borehole to prevent vertical water flow from impacting the soil 22.

[0044] In this embodiment, a plurality of water outlet pipes are vertically arranged on the top plate 201, and a plurality of vertical water outlets are arranged on the water outlet pipes at intervals along the vertical direction of the water outlet pipes. A first water outlet switch 29 and a third rotor flowmeter 30 are arranged on the pipes connected to the vertical water outlets, and a second water outlet switch 31 and a third rotor flowmeter are arranged on the pipes connected to the horizontal water outlets 204.

[0045] The height of the top plate 201 of the model box 20 of this embodiment is adjustable and a water outlet pipe is provided in this embodiment, and vertical water outlets are arranged on the water outlet pipe at intervals along the vertical direction of the water outlet pipe, so that the height of the vertical water outlet and the height of the top plate 201 can be adjusted according to the vertical water pressure / lateral water pressure to cooperate with the vertical water supply subsystem to provide sufficient vertical pressure and vertical water flow.

[0046] In this embodiment, the vertical water supply subsystem includes a first water inlet pipe 3, a vertical water supply tank 10, and a first water filling machine; one end of the first water inlet pipe 3 is connected to the vertical water inlet 1, and the other end is connected to the vertical water supply tank 10; the vertical water supply tank 10 is connected to the air outlet of the first water filling machine; the first water inlet pipe 3 is provided with a first rotor flowmeter 4 and a first valve 2, and the vertical water supply tank 10 is provided with a first pressure gauge 12 and a first exhaust valve 11.

[0047] In this embodiment, the water supply system includes a first water reservoir 6, and the vertical water supply subsystem also includes a first water pump 8 and a first water pumping pipe 71; one end of the first water pumping pipe 71 is arranged in the first water reservoir 6, and the other end is connected to the water suction port of the first water pump 8, and the water outlet of the first water pump 8 is connected to the vertical water supply tank 10.

[0048] In this embodiment, the horizontal water supply subsystem has the same composition structure as the vertical water supply subsystem. In other words, the horizontal water supply subsystem includes a second water inlet pipe, a horizontal water supply tank 15, and a second irrigation machine; one end of the second water inlet pipe is connected to the horizontal water inlet 205, and the other end is connected to the horizontal water supply tank 15; the horizontal water supply tank 15 is connected to the air outlet of the second irrigation machine; the second water inlet pipe is provided with a second rotor flowmeter 18 and a second valve 19, and the horizontal water supply tank 15 is provided with a second pressure gauge 17 and a second exhaust valve 16; the horizontal water supply subsystem also includes a second water pump 13 and a second water pumping pipe 72; one end of the second water pumping pipe 72 is provided in the first water reservoir 6, and the other end is connected to the water pumping port of the second water pump 13, and the water outlet of the second water pump 13 is connected to the horizontal water supply tank 15.

[0049] In this embodiment, the irrigation machine is an air compressor, that is, the first irrigation machine is a first air compressor 9 , and the second irrigation machine is a second air compressor 14 .

[0050] In this embodiment, a water circulation system is also included, which includes a clean water tank and a second water reservoir 34 for receiving water flowing out of the model box 20 . The clean water tank is connected to the first water reservoir through a siphon 5 .

[0051] The sizes of the first water reservoir 6, the vertical water supply tank 10, the horizontal water supply tank 15, the second water reservoir 34 and the clean water tank 42 can be determined according to the experimental design water flow velocity and the sizes of the model box 20, the model pile 28 and the gap 37 to ensure sufficient water flow.

[0052] In this embodiment, a plurality of screw holes 43 are provided at the bottom end of the model pile 28, and the model pile 28 is fixed to the model box 20 by bolts 39. The bottom end of the model pile 28 is sealed by pouring concrete, that is, a concrete sealing layer 36 is provided at the bottom end of the model pile 28.

[0053] The number and length of the bolts 39 should be moderate, so as to fix the model pile 28 without shaking, and 3-5 bolts are suitable. The height of the concrete seal layer 36 should not be too high. The purpose of sealing the bottom end of the model pile 28 is to prevent groundwater or grouting liquid from flowing out of the inner cavity of the model pile 28, causing the test failure. It is preferred that the height of the concrete seal layer 36 be controlled at 10-15 cm.

[0054] The grouting pressure / grouting rate of the grouting system of this embodiment is adjustable, so as to carry out the research on the anti-groundwater dispersion performance of the grouting liquid under different grouting pressures / grouting rates and different water flow coupling. The grouting system includes a grouting machine 23, a third pressure gauge 24, a grouting switch 25, and a grouting pipe 26. One end of the grouting pipe 26 is connected to the grouting machine 23, and the other end is connected to the grouting hole. The pressure gauge 24 and the grouting switch 25 are arranged on the grouting pipe 26.

[0055] Embodiment 2

[0056] like Figure 4 As shown, the present invention also provides a method for testing the water resistance of grouting fluid using the device for testing the water resistance of grouting fluid for pile side of pipe pile while drilling described in the first embodiment, comprising the following steps:

[0057] Inject grout into the gap 37 in a waterless state, take part of the grouting liquid in the gap 37 and obtain the water-cement ratio, density, consistency, fluidity, compressive strength, elastic modulus, and yield strength of the grouting liquid; after the grouting liquid in the gap 37 solidifies to a predetermined strength, obtain the three-dimensional geometric dimensions of the grouting liquid;

[0058] The water supply system is turned on, and grouting is injected into the gap 37 in the presence of water. After the water discharge time of the model box 20 reaches a preset time, part of the grouting liquid in the gap 37 is taken and the water-cement ratio, density, consistency, fluidity, compressive strength, elastic modulus, and yield strength of the grouting liquid are obtained; after the grouting liquid solidifies to a predetermined strength, the water supply system is turned off and the three-dimensional geometric dimensions of the grouting liquid are obtained;

[0059] The water resistance of the grouting liquid is determined based on the change in water-cement ratio, density, consistency, fluidity, compressive strength, elastic modulus, yield strength of the grouting liquid in the anhydrous state and the water state, and the change in the three-dimensional geometric dimensions of the grouting liquid solidified in the anhydrous state and the water state. In this embodiment, before opening the water supply system, the following steps are also included:

[0060] Close the horizontal water supply subsystem and open the vertical water supply subsystem until the water inflow of the vertical water inlet 1 and the water outflow of the vertical water outlet are balanced;

[0061] The vertical water supply subsystem is closed, and the horizontal water supply subsystem is opened until the water inflow of the horizontal water inlet 205 and the water outflow of the horizontal water outlet 204 are balanced;

[0062] The vertical water supply subsystem and the horizontal water supply subsystem are opened until the water inflow of the vertical water inlet 1 and the water inflow of the horizontal water inlet 205 are balanced with the water outflow of the model box 20 .

[0063] Specifically, the method steps for testing the water resistance of the grouting liquid using the device for testing the water resistance of the pile side grouting liquid while drilling pipe piles described in Example 1 include:

[0064] (1) Drill holes at the positions of the pre-designed lower grouting holes 38 and the middle grouting holes 35 on the model pile 28. The number and position of the grouting holes can be adjusted according to the experimental requirements, and the size of the grouting holes should be determined according to the diameter of the grouting pipe 26; use high-strength easy-to-solidify glue (such as 502 glue, AB glue, etc.) to connect and fix different grouting pipes 26 to the lower grouting holes 38 and the middle grouting holes 35 respectively; seal the bottom of the model pile 28 with cement slurry to prevent the grouting liquid from flowing out of the inner cavity of the pipe pile, causing grouting failure. The thickness of the concrete sealing layer 36 is not less than 10 cm. After sealing the bottom, put the model pile 28 aside and wait for the concrete sealing layer 36 to solidify for use;

[0065] (2) A third permeable stone layer 40 is laid on the bottom plate 203 of the model box 20. The thickness of the third permeable stone layer 40 can be determined according to the bottom water pressure, generally about 5 cm. The diameter of the third permeable stone layer 40 is slightly larger than the diameter of the simulated borehole to evenly distribute the water pressure of the model bottom plate 203. After the concrete sealing layer 36 reaches a certain strength, the model pile 28 is bolted to the bottom plate 203 of the model box 20 with bolts 39, and the model pile 28 is protected by a cylindrical steel sleeve 41 to prevent the model pile 28 from being damaged during the filling and compaction process. The diameter of the cylindrical steel sleeve 41 is slightly larger than the diameter of the model pile 28, and the specific size is determined according to the actual grouting gap 37 of the project.

[0066] (3) According to the experimental plan, the soil 22 (not limited to clay, sand, backfill soil, mixed soil, etc.) used in the experiment is selected, and the physical and mechanical parameters of the soil 22 such as density, particle gradation, and specific gravity are measured. The soil is filled in layers from the bottom to the top starting from the bottom plate 203 and saturated with water and compacted. Each layer is 5-10 cm. After compaction, the density of the soil sample is measured. When the density meets the test requirements, the next layer of soil is filled until the soil is filled to the top plate 201 of the model. A second permeable stone layer 21 is required at the same time as each layer of soil filling. When the soil is filled to the top plate 201 of the model, a first permeable stone layer 27 needs to be laid on the top soil layer;

[0067] (4) Pull out the cylindrical steel casing. Since the diameter of the cylindrical steel casing 41 is slightly larger than the diameter of the model pile 28, an annular gap 37, i.e., the grouting gap 37, is formed between the model pile 28 and the soil 22. Then, cover the top plate 201 of the model box 20 and seal it with a sealing rubber gasket to prevent water leakage.

[0068] (5) After completing the above steps, follow Figure 1 Connect the components in a certain way, close the first valve 2 and the second valve 19, close the first exhaust valve 11 and the second exhaust valve 16, turn on the first air compressor 9 and the first air compressor 9, and check the air tightness of the vertical water supply tank 10 and the horizontal water supply tank 15 to ensure that there is no air leakage;

[0069] (6) Turn off the air outlet switches of the first air compressor 9 and the second air compressor 14, open the first exhaust valve 11 and the second exhaust valve 16, and simultaneously turn on the first pumping pump 8 and the second pumping pump 13, extract the groundwater stored in the first water reservoir 6 from the deep stratum through the first pumping pipe 71 and the second pumping pipe 72, and fill the vertical water supply tank 10 and the horizontal water supply tank 15 with water. After filling, turn off the first exhaust valve 11 and the second exhaust valve 16, and simultaneously turn on the air outlet switches of the first air compressor 9 and the second air compressor 14 as well as the first valve 2 and the second valve 19, so as to realize horizontal and vertical water supply to the model box 20;

[0070] (7) According to the actual groundwater flow conditions of the project, the actual lateral and vertical water flow velocities of the formation are obtained, and the actual formation flow velocity is simulated by adjusting the first air compressor 9, the second air compressor 14, the first water outlet switch 29 on the top plate 201, and the second water outlet switch 31 on the model bottom plate 203.

[0071] Before the experiment, the adjustment process of the vertical water supply system included:

[0072] The first pumping pump 8 and the first pumping pipe 71 fill the vertical water supply pool 10 with water, and provide continuous pressure to the vertical water supply pool 10 through the first air compressor 9. Later, the first pumping pump 8 continuously replenishes groundwater to the vertical water supply pool 10 to prevent water outage or water shortage; turn on the first water inlet switch, and the groundwater enters the model box 20 through the vertical water inlet 1 under pressure, and the water pressure is evenly distributed through the third permeable stone layer 40 pre-buried at the bottom of the model box 20 to prevent uneven pressure from causing large deviations in the water flow field. The water inlet Q1 is read through the first rotor flowmeter 4, the first water outlet switch 29 is turned on, and the water outlet Q2 is read through the third rotor flowmeter 30 until the reading of Q2 tends to be stable.

[0073] The regulation process of the horizontal water supply system is consistent with that of the vertical water supply system. The second rotor flowmeter 18 and the fourth rotor flowmeter 33 record the horizontal water inlet Q3 and the water outlet Q4.

[0074] When the sum of the water inflow Q1 and the water inflow Q3 is equal to the sum of the water outflow Q2 and the water outflow Q4 and the water outflow Q2 and the water outflow Q4 are both stable, it indicates that the water flow field in the model box 20 is stable at this time. The vertical and horizontal water flow velocities are calculated by the water outflow Q2 and the water outflow Q4 respectively. If the flow rate is not large enough to meet the requirement, the pressure of the first air compressor 9 and the second air compressor 14 and the height of the first water outflow switch 29 can be adjusted to adjust the flow rate.

[0075] The groundwater flowing out from the vertical water outlet and the horizontal water outlet 204 will flow into the second water reservoir 34. The groundwater in the second water reservoir 34 is regularly poured into the clean water tank 42. The turbid groundwater becomes clear after standing in the clean water tank 42. The clear groundwater in the clean water tank 42 is injected into the first water reservoir 6 through the siphon 5, thereby ensuring that the first water reservoir 6 can provide sufficient groundwater to the vertical water supply tank 10 and the horizontal water supply tank 15, thereby forming a water circulation system to avoid the waste of groundwater.

[0076] (8) After the vertical and horizontal flow rate adjustments are completed, the grouting liquid is prepared according to the ratio (water-cement ratio, admixture content) of the slurry with anti-groundwater dispersion performance to be tested, and the prepared grouting liquid is poured into the grouting machine 23. The grouting pressure is read and controlled by the pressure gauge. The position, number and diameter of the middle grouting hole 35 and the lower grouting hole 38 are set to design and construct a similar grouting process on site. According to the predetermined grouting pressure and grouting process, a grouting test is carried out under the action of groundwater flow. The grouting liquid flows in from the two grouting pipes 26 and flows out from the middle grouting hole 35 and the lower grouting hole 38. After the grouting liquid flows out, it diffuses along the annular gap 37 between the model pile 28 and the surrounding soil. When the grouting liquid diffuses to the position where the model top plate 201 is flush with the top plate 201, the grouting is stopped and the grouting machine 23 is cleaned;

[0077] (9) Due to the interaction between groundwater and grouting liquid, the groundwater flowing out of the vertical outlet and the horizontal outlet 204 contains cement slurry and is turbid. After the groundwater flowing out of the vertical outlet and the horizontal outlet 204 becomes clear for 10 minutes, part of the slurry in the gap 37 is taken out. In the laboratory, the basic physical and mechanical properties of the taken grouting liquid, such as water-cement ratio, density, consistency, fluidity, compressive strength, elastic modulus, and yield strength, are measured. For the convenience of description, they are uniformly numbered as M2;

[0078] (10) After the grouting liquid in the gap 37 solidifies and reaches a certain strength, the water supply system and the water circulation system are closed, and the soil 22 is excavated to obtain the three-dimensional spatial distribution characteristics of the grouting liquid along the pile body (i.e., the grouting body). The three-dimensional spatial geometric dimensions of the grouting body are obtained by a three-dimensional scanner, and the grouting body is quantitatively characterized. The grouting effect is numbered W2;

[0079] (11) Repeat the process from step (8) to step (10), except that the water supply system and the water circulation system are turned off during this process, and a flow test of the grouting liquid on the pile side of the pipe pile while drilling is carried out without the action of groundwater flow, and the flow characteristics of the grouting liquid on the pile side of the pipe pile while drilling is carried out without the action of water; in the same way, take away part of the grouting liquid in the grouting gap 37, and measure the basic physical and mechanical properties of the grouting liquid such as water-cement ratio, density, consistency, fluidity, compressive strength, elastic modulus, and yield strength in the laboratory, and uniformly number them as M1; in the same way, dig the soil body 22 to obtain the three-dimensional spatial distribution characteristics of the grouting liquid along the pile body, and use the three-dimensional spatial geometric dimensions of the grouting body obtained by a three-dimensional scanner to quantitatively characterize the grouting body, and the grouting effect is numbered as W1;

[0080] (12) Compare and analyze the flow characteristics of the lateral grouting of pipe piles while drilling under the action of groundwater flow and without the action of water flow, analyze the changes in the basic physical and mechanical properties of the slurry before and after grouting, such as water-cement ratio, density, consistency, fluidity, compressive strength, elastic modulus, and yield strength (M1 and M2 are compared), study the three-dimensional spatial distribution characteristics of the grouting body along the pile body before and after grouting with water and without water, and quantitatively characterize the change characteristics of the three-dimensional spatial geometric dimensions of the grouting body (W1 and W2 are compared), and test the anti-groundwater dispersion performance of the lateral grouting of pipe piles while drilling based on this.

[0081] The present invention is not limited to the above-mentioned embodiments. If various changes or modifications to the present invention do not depart from the spirit and scope of the present invention, and if these changes and modifications fall within the scope of the claims and equivalent technologies of the present invention, the present invention is also intended to include these changes and modifications.

Claims

1. A device for testing the water resistance of the grouting fluid for pile side injection while drilling, characterized in that: Including model box system, water supply system and grouting system; The model box system comprises a model box and a model pile with a sealed bottom end; the model box is filled with soil, a simulated borehole is arranged in the soil, and the diameter of the simulated borehole is larger than the diameter of the model pile; the model pile is coaxially arranged in the simulated borehole, a side wall of the model box is provided with a plurality of transverse water inlets, a bottom plate of the model box is provided with a plurality of transverse water outlets and a plurality of vertical water inlets, and a top wall of the model box is provided with a plurality of vertical water outlets; The water supply system comprises a horizontal water supply subsystem and a vertical water supply subsystem, the water outlet of the horizontal water supply subsystem is connected to the horizontal water inlet, and the water outlet of the vertical water supply subsystem is connected to the vertical water inlet; The model pile is provided with a plurality of grouting holes for grouting into the gap between the model pile and the soil; the grouting outlet of the grouting system is connected with the grouting holes; A plurality of water outlet pipes are vertically arranged on the top plate of the model box, and a plurality of vertical water outlets are arranged on the water outlet pipes at intervals along the vertical direction of the water outlet pipes, so that the height of the vertical water outlets can be adjusted according to the vertical water pressure or the horizontal water pressure; The vertical water supply subsystem includes a first water inlet pipe, a vertical water supply tank and a first water irrigation machine; One end of the first water inlet pipe is communicated with the vertical water inlet, and the other end is communicated with the vertical water supply tank; the vertical water supply tank is communicated with the air outlet of the first irrigation machine.

2. The device for testing the water resistance of the pile side grouting fluid while drilling according to claim 1, characterized in that: A first permeable stone layer is laid between the top plate of the model box and the soil, a second permeable stone layer is laid between the side wall and the soil, and a third permeable stone layer is evenly laid between the bottom end of the simulated borehole and the bottom plate of the model box; the lateral water outlet is arranged on the bottom plate of the model box at a position corresponding to the second permeable stone layer, and the vertical water inlet is arranged on the bottom plate of the model box at a position corresponding to the third permeable stone layer.

3. The device for testing the water resistance of the pile side grouting fluid while drilling according to claim 1, characterized in that: The first water inlet pipe is provided with a first rotor flowmeter and a first valve.

4. The device for testing the water resistance of the pile side grouting fluid while drilling according to claim 1, characterized in that: The vertical water supply tank is provided with a first pressure gauge and a first exhaust valve.

5. The device for testing the water resistance of the pile side grouting fluid while drilling according to claim 3, characterized in that: The water supply system includes a first water reservoir, and the vertical water supply subsystem also includes a first water pump and a first water pumping pipe; one end of the first water pumping pipe is arranged in the first water reservoir, and the other end is connected to the water suction port of the first water pump, and the water outlet of the first water pump is connected to the vertical water supply tank.

6. The device for testing the water resistance of the pile side grouting fluid while drilling according to claim 5, characterized in that: It also includes a water circulation system, which includes a clean water tank and a second water reservoir for receiving water flowing out of the model box, and the clean water tank is connected to the first water reservoir through a siphon.

7. A method for testing the water resistance of grouting fluid using the device for testing the water resistance of grouting fluid for pile side while drilling as claimed in any one of claims 1 to 6, characterized in that: The steps include: In a water-free state, grouting is performed into the gap, a portion of the grouting liquid in the gap is taken and the water-cement ratio, density, consistency, fluidity, compressive strength, elastic modulus and yield strength of the grouting liquid are obtained; after the grouting liquid in the gap solidifies to a predetermined strength, the three-dimensional geometric dimensions of the grouting liquid are obtained; The water supply system is turned on, and grouting is injected into the gap in the presence of water. After the water discharge time of the model box reaches a preset time, part of the grouting liquid in the gap is taken and the water-cement ratio, density, consistency, fluidity, compressive strength, elastic modulus and yield strength of the grouting liquid are obtained; after the grouting liquid solidifies to a predetermined strength, the water supply system is turned off and the three-dimensional geometric dimensions of the grouting liquid are obtained; The water resistance of the grouting fluid is judged based on the changes in the water-cement ratio, density, consistency, fluidity, compressive strength, elastic modulus and yield strength of the grouting fluid in the anhydrous state and in the presence of water, as well as the change characteristics of the three-dimensional spatial geometric dimensions of the solidified grouting fluid in the anhydrous state and in the presence of water.

8. The method for testing the water resistance of grouting fluid according to claim 7, characterized in that: Before opening the water supply system, the following steps are also included: The horizontal water supply subsystem is closed, and the vertical water supply subsystem is opened until the water inflow of the vertical water inlet and the water outflow of the vertical water outlet are balanced; The vertical water supply subsystem is closed, and the horizontal water supply subsystem is opened until the water inflow of the horizontal water inlet and the water outflow of the horizontal water outlet are balanced; The vertical water supply subsystem and the horizontal water supply subsystem are opened until the water inflow of the vertical water inlet and the water inflow of the horizontal water inlet are balanced with the water outflow of the model box.

Images